Synthetic rubber composition



Reissued Sept. 17, 1940 Emil Ott, Els mere, Powder Company, tion of Delaware No Drawing. 0

M, allgnor to Hercules ilmington Del., a corporam. 2.138.102, am Nol ll vember 29, 1938, Serial N0..61,759, January 31,

1936. Serial No; 341,785

14 C aims.

My invention relates to a synthetic rubber composition and more specifically to a synthetic rubber composition comprising polymerized chloro prene and chlorinated paraflin. 6 Synthetic rubber compositions including polymerized chloroprene as a base, show considerable advantage over similar compositions including natural rubber as a base, in that they possess higher resistance to solvents, particularly-gasoline and mineral oils, and show less loss of desirable physical properties on exposure to solvents. For this reason, such synthetic rubber compositions have found, wide application in the manufacture of-g'asolinehose, gaskets and other articles which come into' contact with solvents. Suchcompositions are, however, not entirely resistant to swelling in solvents and further improvement is desirable- I have invented a synthetic rubber composition which is highly resistant to the swelling action of gasoline and mineral oils, which comprises essentially polymerized chloroprene and a chlorinated paraflin wax having a chlorine content suiliciently high to render the said wax insoluble in gasoline.

The chlorinated paraflin wax used in the compositions, in accordance with my invention, will desirably have a chlorine content of not less than about 52% by weight, and may have as high a chlorine content as can be obtained. The practical upper limit appears to be about 62% by .weight. The chlorine content of the chlorinated paramn wax, used in accordance with this invention will, then, be within the range of about 52% to about 62% by weight. The chlorinated paraffin wax will, desirably, be stabilized by treatment with aqueous alkaline solutions, as morecompletely described in the copending application for United States Letters Patent of William T. Bishop, Serial No. 15,505, filed-April 9, 1935; and/or stabilized by the addition of organic bases, as more completely described in my copending application filed jointly with William T. Bishop, Serial No. 19,468, filed May 2, 1935.

The polymerized chloroprene used in the composition, in accordance with my invention is the unvulcanized, chloroprene polymer having physical properties very similar to those of natural rubber. Such polymerized chloroprene is known to the art by the trade name of Duprene.

-In addition to chlorinated parallin and polyinerlaed chloroprene, the compositions in accordance with my invention may include vulcanizing agents, for example, metallic oxides, as, magnesium oxide, zinc oxide, lead oxide, abietic acid Application for containing compounds, as, wood rosin. pine tar, etc., vulcanization accelerators, sulfur, etc., they may contain rubber anti-oxidants, such as a phenyl-naphthyla'mine, for example, phenylalpha-naphthylamine (Neozone A), phenyl-beta naphthylamlne (Neozone D), etc.; they may contain reinforcing pigments, such as, carbon blacks, clay, blanc flxe, etc: they may contain fillers and/or diluents, such as whiting," barytes, asbestine, factice, rubber, various, synthetic plastics, glue, etc.; they'may contain softeners, such as, paraflin wax, fatty acids, oils. tars, cumar resins, et c. and they may contain deodora'nts, such as terpene compounds, etc.

The composition in accordance with my inven- .tionmay contain chlorinated paramn wax in amount'within the range of-about 1% to about 100% by weight based on the amount of polymerized chloroprene present, and will preferably contain chlorinated paramn wax in amount within the range of about 30% to about 70% by weight 'of the polymerized chloroprene present.

The chlorinated paraflin wax-polymerized chloroprene composition may be vulcanized by heat alone with'no additional ingredients present. It will be found, however, that the properties of this composition will be enhanced by compounding it with other ingredients. Thus, for example. wood rosin sulfur, metallic oxides, etc., may be advantageously compounded into the composition before vulcanization. The addition of wood rosin, abietic acidor pine tar will be found to be highly desirable. v

The wood rosinor abletic acid may be added in amounts up to about 5% of the weight of the polymerized chloroprene present, and the pine tar may be added in amountsup to about 10%. When using pine tar in amounts above 5% by weight of the chloroprenepresent, it is usually necessary to reduce the amount of softener contained in the composition, as the pine tar has a softening action on the composition.

Sulfur may be added in amounts up to about 3% by weight of the polymerized chloroprene present. When added in excessive amounts the sulfur tends to "bloom" out of the composition. The exact amount that may be added depends on the various ingredients present in the composition. The metallic oxide added to the composition may be, for example, magnesia, zinc oxide, lead oxide, or combinations of these materials. Such oxides are valuable additions to the composition in that they improve the physical properties of the composition and, in addition, act as acceptors for any hydrochioricacid which may 5.

reissue June. 21, 1940,

amine in amounts within the range of about 1% to about 5% by' weight of the polymerized chloroprene in the composition. Carbon blacks. such as, for example, channel carbon black or "soft blacks" may be advantageously added to the composition. Such. carbon blacks may be added in amounts up to 100-200% by weight of the total weight of chlorinated parailin wax and polymerized chloroprene, depending upon the exact carbon black used. Glue may be, added in amounts up to about 25% by weight.

Various softeners, such as, for example, parainn wax, fatty acids, oils, tars. waxes, cumarone resins,-etc.. may, if desired, be added to the come position. Such additions are usually not ,desira- I ble. since they tend to decrease the resistance of the composition to gasoline and ofls. Chlorinated paraflin wax acts as a softener tor the composition. and any desired softness may be obtained by increasing the percentage'oi' chlorinated paraflln contained in the composition, with out decreasing the oil and gasoline resistance.

As examples of compositions. in accordance with this invention, the following maybe cited:

Example I Parts 0 Polymerized chloroprene'. 3 Chlorinated paraflin wax (50% chlorine)...... 1

Example II Parts Polymerized chloroprene 4 Chlorinated paraiiin wax chlorine); l

'Ihe compositions according to the above examples may be dissolved in an, aromatic hydro-.

tions of compositions, in accordance with my invention, which are suitable for vulcanization.

v Example 3 Example 4 f Ports Po zed chioroprsne Do as) 151i, 0 287 O wax 5i ehlorine)... 75.0 140 Carbon bisc 197.5 369 Will 153. 0 287 Z l5. 3 28. 7 tar 10. 2 l9. 1 Cumarone-indenc resin (Cum P25 10. 2 l9. 1 Wood rosin (Color FR). 10.2 10. 1 Li i calcined magnesia 16.3. at 7 ur l. 3 2. 4 Btearic acid 2. 5 a 4. 8 Phenyl-dpha-nsphthylamine l. 3 2. 4

The compositions shown inthese examples may be vulcanized following the procedure used by the prior art with similar compositions of poly- It will be understood that the was and examples hereinbefore set forth are illustrative 01117. 1! that the invention as herein broadly described-and ciaimed'is in no way limited thereby.

What]: claim-and desire to protect by United States Letters Patcntis:

I.A= synthetic rubber compositionyincluding polymerized chloroprene and ajgasoline insoluble chlorinated parafiin wax, the said composition byhighresistancetoswelling inzgasoline. I

2. A synthetic rubber composition including polymerized chloroprene and a chlorinated paraiiin' having a chlorine content of not less than about 52% by weight, the said composition being characterized by high resistance to swellinsingasoline. a

3. A synthetic rubber composition including polymerized chloroprene and a chlorinated par-. ailln wax having a chlorine content within the range of \about. 52% to about 62% by weight, the sold compositionbe'ing characterized by high resistancetoswellingingasoline.

4. A synthetic rubber composition including polymerized chloroprene, a vulcanizing agent, and chlorinated paraiiin wax having a chlorine content of not less than about 52% by weight,

the said composition being characterized by high resistance to swelling l gasoline.

5. A synthetic rubber composition inclu polymerized chloroprene, a metallic oxide. and

chlorinated paraiiin wax having a chlorine content of not less than about 52% by weight, the said composition beingcharacterized by high resistance to swelling in gasoline.

'6. A synthetic rubber composition including polymerized chloroprene, magnesium oxide, and

chlorinated having a'chlorine content of i not less than about 52%, the said composition being characterized by high resistance to swelling in gasoline.

'l. A synethic rubber composition including polymerized chloroprene, an anti-oxydant, and chlorinated paraflin wax having a chlorine content of not less than about 52% by weight, the said composition being characterized by high resistance to swelling in gasoline.

\ 8 A synthetic rubber composition including polymerized chloroprene, a phenyl-naphthylamine, and chlorinated paraiiin having a chlorine content of not less than about 52%, the said composition being characterized by high resistance to swelling in gasoline.

9. A synthetic rubber composition including polymerized chloroprene, phenyl-alpha-naphthylamine, and chlorinated paraflin having a chlorine content of not less than about 52%, the said composition being characterized by high resistance to swelling in gasoline.

2 10. A synthetic rubber composition including polymerized chloroprene, a reinforcing pigment and chlorinated parailin having a chlorine content of not less than about 52%, the said composition beingcharacterized by high resistance to swelling in gasoline.

11. A synthetic rubber composition including i polymerized chloroprene, a carbon black, and

chlorinated paramn having a chlorine content of not less than about 52%, the said composition being characterized by highresistance to swelling in gasoline.

12. A synthetic rubber composition consisting of a, vulcanized mixture including polymerized chloroprene and a gasoline insoluble chlorinated 7 paraflln wax, in; said composition being characterized by high resistance to swelling in gasoline.

18. A synthetic rubber composition consisting.

composition being characterized by high resistance to swelling in gasoline.

14. A synthetic rubber compositionconsisting of a. vulcanized mixture including polymerized chloroprene, a. vulcanizing agent, and chlorinated paraflln wax having a chlorine content of not less than 52% by weight and being insoluble in gasoline, the said composition being characterized by high resistance to swelling in gasoline. 

